Whitespace fix.

src/mail/ngx_mail_core_module.c

diff --git a/src/mail/ngx_mail_core_module.c b/src/mail/ngx_mail_core_module.c
index 86d0b3b..be8673c 100644
--- a/src/mail/ngx_mail_core_module.c
+++ b/src/mail/ngx_mail_core_module.c
@@ -391,13 +391,13 @@
             if (ngx_modules[m]->type != NGX_MAIL_MODULE) {
                 continue;
             }
-    
+
             module = ngx_modules[m]->ctx;
-    
+
             if (module->protocol == NULL) {
                 continue;
             }
-    
+
             for (i = 0; module->protocol->port[i]; i++) {
                 if (module->protocol->port[i] == u.port) {
                     cscf->protocol = module->protocol;